This invention relates to improvements in an air bag module which is mounted on a vehicle and includes an air bag which inflates and deploys to protect passengers at the event of a vehicle collision or the like.
Nowadays, a number of stock-cars are provided with an air bag module for a passenger at a front passenger seat as means for improving safety to the passenger at the event of the collision. By the way, it is required for an instrument panel of an automotive vehicle to have a function for absorbing energy of striking of the passenger to the instrumental panel upon gradual deformation of the instrument panel when the passenger comes into striking against the instrument panel. In other words, the instrument panel is required to have a function to absorb an impact upon deforming the side of an air bag module to prevent an excess impact from being transmitted to the passenger not only when the air bag is required to deploy at an accident or the like but also when the head or hand of the passenger unavoidably hits against the instrumental panel to which the air bag is mounted.
Along with this requirement, a technique is disclosed in Japanese Patent Provisional Publication No. 2001-63503, in which this air bag module includes a case having an opening at its front side. The case accommodates therein and connects with an air bag. The air bag is supplied with gas generated by a gas generator (or an inflator) so as to be inflated. The opening of the case is covered with a lid member. The case is fixedly provided at its side surfaces with thick plates. At least a part of the rear section of the thick plate is fixed on the side surface of the case. The part of the rear section of the thick plate and a side section (to which the rear section of the thick plate is fixed) of the case project outside.
According to the above technique, the thick plate increases the rigidity of the case so that the opening of the case is prevented from being expanded upon deformation of the case to which the deploy pressure of the air bag is applied. Additionally, when an impact of the passenger is applied to the instrumental panel during non-deploy of the air bag, the thick plate deforms the case to absorb energy of the impact to the instrumental panel, so that a reaction force of impact of the passenger to the instrumental panel is reduced. Specifically, when the impact is applied, the case is bent at its portion near a bent portion of the thick plate. Therefore, the upper end of the thick plate will enter an air bag accommodating chamber which is defined within the case, deforming the case.